This application claims priority to Chinese Application Serial Number 201410244249.7, filed on Jun. 4, 2014, which is herein incorporated by reference.
Field of The Invention
The disclosure relates to touch display devices, and more particularly to touch display devices with faded etching marks and optical compensation.
Related Art of Invention
Touch display devices typically include a cover glass, a touch sensing unit, an upper polarizer, a liquid crystal unit, a lower polarizer, a backlight unit, etc. The aforesaid elements are stacked in sequence from top to bottom. A touch sensing electrode in the touch sensing unit is made from a transparent conductive material (such as a nano silver) that is subjected to a patterning process. However, since the optical properties of a touch sensing electrode and an electrode substrate are different, in some situations, users will observe the shape of the touch sensing electrode (i.e., an etching mark), thereby adversely affecting the quality of a displayed image.
The electrode substrate of the aforesaid touch sensing unit can be made of a transparent hard material (such as glass), or can be made of a transparent soft material (such as polyethylene terephthalate (PET)). For an electrode substrate made of polyethylene terephthalate (PET), the optical properties of the light generally remain unchanged prior to and after passing therethrough. However, uneven surfaces and unexpected structural stress in parts of the electrode substrate will cause the optical properties (e.g., polarization) of the light passing through these parts of the electrode substrate to change, thereby affecting the overall optical properties of the touch display device.